The present invention relates to a lock cylinder opening system and method and, in particular, it concerns a retrofittable system that can be operated to electrically open a cylinder lock, such as used in doors, with minimal power utilization and one which may also be operated conventionally with a key.
In a conventional mechanical cylinder lock, when an appropriate matching key is inserted into the cylinder lock, the key serves to mechanically align tumbler pins (“unlocked” or “opened” state), allowing the cylindrical plug to be rotated freely to retract a bolt which is typically mechanically connected the cylindrical plug and is driven by the rotated cylindrical plug. Retraction of the bolt is typically referred to as “unbolting” the lock. Conversely, when the cylindrical plug is rotated (usually in a direction opposite that used for unbolting) and the bolt is extended in such a way as to inhibit movement of a door or window, etc. the action is referred to as “bolting” the lock. Following bolting, the key is typically withdrawn from the key slot, the tumbler pins are not aligned, which inhibits free rotation of the cylindrical plug, and the lock is then in a “locked” or “closed” state.
In a conventional mechanical cylinder lock, when an appropriate matching key is inserted into the cylinder lock, the key serves to mechanically align tumbler pins, and thereby allowing the cylindrical plug to be rotated freely to open the lock. Referring now to FIGS. 1A and 1B, which are representations of a prior art cylinder lock 10, with a key 12 inserted into the cylinder lock, and a door lock 15. Door lock 15 includes, inter alia, a shaped slot 16 for receiving cylinder lock 10 and a door lock hole 17 through which a bolt (not shown) is inserted to secure the cylinder lock inside the door lock. Typically, door lock 15 is inserted into a hollowed-out edge of the door (not shown) and cylinder lock 10 is inserted through prepared holes in the door (not shown in the figure) and perpendicularly into and through shaped slot 16, substantially along axis 18. Door lock further includes a bolt 19. Typically, cylinder lock 10, when unlocked, serves to translate bolt 19 into the door lock, so that bolt 19 is substantially flush and the door lock is referred to as “unbolted”. When bolt 19 translated out of door lock 15, the door lock is “bolted”. Typically, other cylinder locks having a cross-sectional profile and length substantially matching cylinder lock 10 may be replaced or retrofitted instead of cylinder lock 10. Typical names/manufacturers of such cylinder locks include, but are not limited to: Euro Cylinders; Oval Cylinders; Asec 6-pin Euro profile; and Chubb M3. Overall lengths of such cylinders typically vary from approximately 60-110 mm.
Reference is now made to FIG. 2, which is a cross sectional side view of the cylinder lock shown in FIG. 1A. The cylinder lock has a body housing 20, which is bored from one end to the other end and a cylindrical plug 22, which is fitted into the bore, and which may be rotated, as described hereinbelow. A set hole 23 is located approximately in the middle of cylinder lock 10 to typically receive a threaded bolt (not shown in the figure) which is inserted into lock hole 17, to secure the cylinder lock within door lock 15, as described hereinabove in FIG. 1B. Cylindrical plug 22 has a key slot 25 formed axially in cylindrical plug. Key 12 is inserted into slot 25. A pin-tumbler set 30 is located in body housing 20 and in cylindrical plug 22 to serve to lock and unlock rotational movement of cylindrical plug 22. Cylindrical plug 22 and a second cylindrical plug 31 may be mechanically coupled and uncoupled to a rotating tongue 35 by means of a clutch unit (not shown in the figure), which allows either of the two cylindrical plugs to rotate the rotating tongue, which in turn serves to move the bolt of the door lock (refer to FIG. 1B). The cylinder lock shown in FIG. 2 is called a “blind cylinder”, in that a key can be inserted into only one side of the lock. However, cylinder lock 10 may also comprise pin-tumbler sets and key slots in respective cylindrical plugs at both ends.
A number of prior art electronic or combination electrical/mechanical lock systems allow a user to open a locked cylinder in a number of ways. In U.S. Pat. No. 3,889,501 by Fort, whose disclosure is incorporated herein by reference, a combination electrical and mechanical system is described. The system includes a lock having a fixed lock cylinder and a rotatable key slug. A first solenoid is employed in the current system to drive a lock pin, which is normally extended to lock the key slug. Upon insertion of an appropriately aperture-encoded key, light sources and detectors mounted in the lock are used in concert with appropriate circuitry to operate to the first solenoid to unlock key slug. A second solenoid is operable, in response to an electrical power failure, to extend a bolt pin. When the bolt pin is extended a proper mechanical key is inserted and rotated, extension of the lock pin is prevented. A proper mechanical key can be inserted to move a plurality of spring loaded pin tumblers in the lock to enable rotation of the key slug during an electrical power failure.
Fonea, in U.S. Pat. No. 6,147,622, whose disclosure is incorporated herein by reference, discloses an electronic lock system which is also manually operable to drive a lock cylinder to move a lock mechanism which includes at least one bolt. The system includes a bidirectional motor engagable with the lock cylinder. At least one sensor in the lock system is used in conjunction with an angular measurement device and/or stepper motor feedback to provide a level of lock self diagnostics and self testing. The system may also be operated in a mechanical manner. Additional features of the lock system, not related to the capabilities noted hereinabove are also disclosed.
While the prior art includes an array of combination electrical/mechanical lock systems of varying complexity and systems that employ motorized opening of a cylindrical lock, the problem of relatively high power necessary to open the cylinder lock and to bolt and unbolt the door remains. Attempts to solve this problem necessitate employing systems with limited reliability, especially when onboard power is necessary to power motors. There is therefore a need for a combination electrical/mechanical lock cylinder opening system that has the capability to be operated with high reliability over time, utilizing little power, and which can easily be retrofitted to an existing lock installation. The system should be remotely operated to allow unbolting and bolting of the lock and to allow the same operations to be performed in a conventional manual manner in case of an electrical power failure. Furthermore, such a system should be integrated with capabilities of electrically and manually locking and unlocking the lock.